HTTP請求方法（可直接copy至你的工具類，屢試不爽）

import com.alibaba.fastjson.JSONObject;
import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Iterator;
import java.util.Map;

/**
 * HTTP傳送post、put請求，帶header、body的方法，獲取結果
 * @param url
 * @param requestMethod POST、PUT
 * @param headerMap
 * @param contentMap
 * @author yswKnight
 * @return
 */
 

public static String httpRequest(String url, String requestMethod, Map<String, String> headerMap, JSONObject contentMap) {
	String result = "";
	try {
		URL restURL = new URL(url);
		HttpURLConnection connection = (HttpURLConnection) restURL.openConnection();
		connection.setRequestMethod(requestMethod)
 
;
		connection.setDoInput(true);
		connection.setDoOutput(true);
		Iterator headerIterator = headerMap.entrySet().iterator();          //迴圈增加header
		while(headerIterator.hasNext()){
			Map.Entry<String,String> elem = (Map.Entry<String, String>) headerIterator.next();
			connection.setRequestProperty
 
(elem.getKey(),elem.getValue());
		}

		OutputStreamWriter outer = null;
		outer = new OutputStreamWriter(connection.getOutputStream(), "UTF-8");
		outer.write(contentMap.toString());
		outer.flush();
		outer.close();
		InputStream ips = connection.getInputStream();

		BufferedReader in = new BufferedReader(new InputStreamReader(ips, "UTF-8"));
		StringBuffer buffer = new StringBuffer();
		String line = "";
		while ((line = in.readLine()) != null) {
			buffer.append(line);
			buffer.append("\r\n");
		}
		in.close();
		ips.close();
		connection.disconnect();
		//得到結果
		result = buffer.toString();
	} catch (IOException e) {
		e.printStackTrace();
	}
	return result;
}

客戶端呼叫程式碼

public static void main(String[] args) {
	try {
		String url = "http://localhost:8090/project/method";
		//封裝請求引數
		//訊息請求頭Headers
		Map<String, String> headersMap = new HashMap<String, String>();
		headersMap.put("Content-Type","application/json; charset=utf-8");
		headersMap.put("appmark","應用標識");
		headersMap.put("sign","加密後的簽名");
		//請求實體body(json格式)
		JSONObject contentMap = new JSONObject();
		contentMap.put("IdCard","3216520000000000218");
		contentMap.put("name","張三");
		String post = HttpClientUtil.httpRequest(url,"PUT", headersMap, contentMap);
		//輸出請求介面獲取的資訊
		System.err.println(post);
	} catch (Exception e) {
		logger.error("HTTP請求異常，原因:"+e.fillInStackTrace());
	}
}